U.S. patent number 10,818,732 [Application Number 16/574,055] was granted by the patent office on 2020-10-27 for photosensitive sensor, manufacturing method of the same, and electronic device.
This patent grant is currently assigned to BOE TECHNOLOGY GROUP CO., LTD.. The grantee listed for this patent is BOE TECHNOLOGY GROUP CO., LTD.. Invention is credited to Renquan Gu, Fang He, Wei He, Dongsheng Li, Shipei Li, Wusheng Li, Huili Wu, Sheng Xu, Qi Yao, Dongsheng Yin, Ying Zhao.
United States Patent |
10,818,732 |
Li , et al. |
October 27, 2020 |
Photosensitive sensor, manufacturing method of the same, and
electronic device
Abstract
A photosensitive sensor and a method of manufacturing the
photosensitive sensor are disclosed. The photosensitive sensor
includes a thin film transistor and a photosensitive element on a
substrate, wherein the photosensitive element includes a first
electrode, a second electrode, and a photosensitive layer between
the first electrode and the second electrode. The second electrode
is connected to a drain electrode of the thin film transistor. An
orthographic projection of an active layer of the thin film
transistor on the substrate is within an orthographic projection of
the second electrode on the substrate. The second electrode
includes at least two stacked conductive layers, at least one of
the at least two stacked conductive layers being a light shielding
metal layer.
Inventors: |
Li; Shipei (Beijing,
CN), Li; Wusheng (Beijing, CN), Yao; Qi
(Beijing, CN), Li; Dongsheng (Beijing, CN),
He; Fang (Beijing, CN), Wu; Huili (Beijing,
CN), Gu; Renquan (Beijing, CN), Xu;
Sheng (Beijing, CN), He; Wei (Beijing,
CN), Yin; Dongsheng (Beijing, CN), Zhao;
Ying (Beijing, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
BOE TECHNOLOGY GROUP CO., LTD. |
Beijing |
N/A |
CN |
|
|
Assignee: |
BOE TECHNOLOGY GROUP CO., LTD.
(Beijing, CN)
|
Family
ID: |
1000005144055 |
Appl.
No.: |
16/574,055 |
Filed: |
September 17, 2019 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200091246 A1 |
Mar 19, 2020 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L
51/0097 (20130101); H01L 51/003 (20130101); H01L
27/307 (20130101); H01L 51/442 (20130101); H01L
29/7869 (20130101); H01L 29/78669 (20130101); H01L
2251/308 (20130101); H01L 29/78633 (20130101) |
Current International
Class: |
H01L
27/30 (20060101); H01L 51/00 (20060101); H01L
51/44 (20060101); H01L 29/786 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
105095872 |
|
Nov 2015 |
|
CN |
|
206058227 |
|
Mar 2017 |
|
CN |
|
107359168 |
|
Nov 2017 |
|
CN |
|
108336100 |
|
Jul 2018 |
|
CN |
|
Other References
First Chinese Office Action dated Mar. 18, 2020, received for
corresponding Chinese Application No. 201811086483.6, 12 pages.
cited by applicant.
|
Primary Examiner: Kusumakar; Karen
Attorney, Agent or Firm: Kinney & Lange, P.A.
Claims
What is claimed is:
1. A photosensitive sensor, comprising: a thin film transistor on a
substrate; a passivation layer above the thin film transistor,
wherein an entirety of an upper surface of the passivation layer is
a planar surface; a planarization layer above the passivation layer
and directly contacting with the upper surface of the passivation
layer, wherein an entirety of an upper surface of the planarization
layer is a planar surface; and a photosensitive element above the
planarization layer and directly contacting the upper surface of
the planarization layer, wherein the photosensitive element
comprises a first electrode, a second electrode, and a
photosensitive layer between the first electrode and the second
electrode, and the second electrode is connected to a drain
electrode of the thin film transistor through a via hole
penetrating through the planarization layer and the passivation
layer; and wherein an entirety of the first electrode is a planar
electrode, an entirety of the photosensitive layer is a planar
layer, and wherein an orthographic projection of an active layer of
the thin film transistor on the substrate is within an orthographic
projection of the second electrode on the substrate, and the second
electrode comprises at least two stacked conductive layers, at
least one of the at least two stacked conductive layers being a
light shielding metal layer.
2. The photosensitive sensor according to claim 1, wherein the
photosensitive layer is made of an organic photosensitive
material.
3. The photosensitive sensor according to claim 2, wherein one of
the at least two stacked conductive layers is directly in contact
with the photosensitive layer and is made of indium tin oxide.
4. The photosensitive sensor according to claim 3, wherein the
second electrode comprises three conductive layers, and the three
conductive layers are formed of indium tin oxide, silver, and
indium tin oxide, respectively.
5. The photosensitive sensor according to claim 1, wherein the
first electrode is a transparent conductive layer.
6. The photosensitive sensor according to claim 1, wherein the
light shielding metal layer is formed of at least one of Cu, Ag,
Al, Mo, or Ti.
7. The photosensitive sensor according to claim 1, wherein the
substrate is a flexible substrate.
8. The photosensitive sensor according to claim 7, wherein the thin
film transistor comprises: a gate electrode on the flexible
substrate, a gate insulating layer on the gate electrode, an active
layer and a source electrode connected to the active layer, and the
drain electrode connected to the active layer on the gate
insulating layer; and wherein the passivation layer is above the
active layer, the source electrode and the drain electrode of the
thin film transistor, an entirety of an upper surface of the gate
insulating layer is a planar surface.
9. The photosensitive sensor according to claim 8, wherein a side
surface of the via hole is perpendicular to the upper surface of
the passivation layer and the upper surface of the planarization
layer.
10. An electronic device, comprising: the photosensitive sensor
according to claim 1.
11. A method of manufacturing a photosensitive sensor, comprising:
forming a thin film transistor on a substrate; forming a
passivation layer above the thin film transistor; wherein an
entirety of an upper surface of the passivation layer is a planar
surface; forming a planarization layer above the passivation layer
and directly contacting with the upper surface of the passivation
layer, wherein an entirety of an upper surface of the planarization
layer is a planar surface; and forming a photosensitive element
above the planarization layer and directly contacting the upper
surface of the planarization layer; wherein forming the
photosensitive element comprises forming a first electrode, a
second electrode, and a photosensitive layer between the first
electrode and the second electrode, and the second electrode is
connected to a drain electrode of the thin film transistor through
a via hole penetrating through the planarization layer and the
passivation layer; wherein an entirety of the first electrode is a
planar electrode, an entirety of the photosensitive layer is a
planar layer, and wherein forming the second electrode comprises:
forming the second electrode by using at least two stacked
conductive layers, wherein an orthographic projection of an active
layer of the thin film transistor on the substrate is within an
orthographic projection of the second electrode on the substrate,
and at least one of the at least two stacked conductive layers is a
light shielding metal layer.
12. The method according to claim 11, wherein one of the at least
two stacked conductive layers is directly in contact with the
photosensitive layer and is made of indium tin oxide.
13. The method according to claim 12, wherein forming the second
electrode specifically comprises: forming the second electrode
comprising three conductive layers, wherein the three conductive
layers are respectively made of indium tin oxide, silver, and
indium tin oxide.
14. The method according to claim 11, wherein the light shielding
metal layer is formed of at least one of Cu, Ag, Al, Mo, or Ti.
15. The method according to claim 11, wherein: the substrate is a
flexible substrate; before forming the thin film transistor on the
substrate, the method further comprises: providing a rigid
substrate; and forming the flexible substrate on the rigid
substrate; and forming the thin film transistor on the substrate
comprises: forming a gate electrode of the thin film transistor on
the flexible substrate; forming a gate insulating layer covering
the gate electrode; forming an active layer of the thin film
transistor on the gate insulating layer; and forming a source
electrode and a drain electrode of the thin film transistor,
wherein the source electrode and the drain electrode are connected
to the active layer.
16. The method according to claim 15, further comprising: stripping
the flexible substrate off the rigid substrate to form a flexible
photosensitive sensor.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to the Chinese patent application
No. 201811086483.6 filed in China on Sep. 18, 2018, a disclosure of
which is incorporated herein by reference in its entirety.
TECHNICAL FIELD
The present disclosure relates to the field of display technology,
and in particular, relates to a photosensitive sensor, a method of
manufacturing the photosensitive sensor, and an electronic
device.
BACKGROUND
Optical sensors have a tendency to be lightweight and widely used.
In related photosensitive sensors, a thin film transistor is
combined with a photosensitive element. External light may affect
performance of the thin film transistor.
SUMMARY
The present disclosure provides a photosensitive sensor, a method
of manufacturing the photosensitive sensor, and an electronic
device.
In a first aspect, a photosensitive sensor is provided. The
photosensitive sensor includes a thin film transistor and a
photosensitive element on a substrate, wherein the photosensitive
element includes a first electrode, a second electrode, and a
photosensitive layer between the first electrode and the second
electrode; the second electrode is connected to a drain electrode
of the thin film transistor; an orthographic projection of an
active layer of the thin film transistor on the substrate is within
an orthographic projection of the second electrode on the
substrate; the second electrode includes at least two stacked
conductive layers, at least one of the at least two stacked
conductive layers is a light shielding metal layer.
Optionally, the photosensitive layer is made of an organic
photosensitive material.
Optionally, one of the at least two stacked conductive layers is in
contact with the photosensitive layer and is made of indium tin
oxide.
Optionally, the second electrode includes three conductive layers,
and the three conductive layers are formed of indium tin oxide
silver, and indium tin oxide, respectively.
Optionally, the first electrode is a transparent conductive
layer.
Optionally, the light shielding metal layer is formed of at least
one of Cu, Ag, Al, Mo, or Ti.
Optionally, the substrate is a flexible substrate.
Optionally, the thin film transistor includes: a gate electrode on
the flexible substrate; a gate insulating layer on the gate
electrode; an active layer and a source electrode connected to the
active layer and a drain electrode connected to the active layer on
the gate insulating layer; the photosensitive sensor further
includes a passivation layer on the active layer, the source
electrode and the drain electrode of the thin film transistor, and
a planarization layer on the passivation layer.
Optionally, the second electrode is connected to the drain
electrode of the thin film transistor through a via hole
penetrating through the planarization layer and the passivation
layer.
In a second aspect, an electronic device is further provided in the
present disclosure. The electrode device includes the
photosensitive sensor according to the above.
In a third aspect, a method of manufacturing a photosensitive
sensor is further provided in the present disclosure. The method
includes: forming a thin film transistor, a first electrode of a
photosensitive element, a second electrode of the photosensitive
element, and a photosensitive layer of the photosensitive element
between the first electrode and the second electrode on a
substrate; wherein, forming the second electrode includes: forming
the second electrode by using at least two stacked conductive
layers, wherein the second electrode is connected to a drain
electrode of the thin film transistor through a via hole, an
orthographic projection of an active layer of the thin film
transistor on the substrate is within an orthographic projection of
the second electrode on the substrate, at least one of the at least
two stacked conductive layers is a light shielding metal layer.
Optionally, one of the at least two stacked conductive layers is in
contact with the photosensitive layer and is made of indium tin
oxide.
Optionally, forming the second electrode specifically includes:
forming the second electrode including three conductive layers,
wherein the three conductive layers are respectively made of indium
tin oxide, silver, and indium tin oxide.
Optionally, the light shielding metal layer is formed of at least
one of Cu, Ag, Al, Mo, or Ti.
Optionally, the substrate is a flexible substrate, forming the thin
film transistor, the first electrode of the photosensitive element,
the second electrode of the photosensitive element, and the
photosensitive layer of the photosensitive element between the
first electrode and the second electrode on the substrate,
specifically includes: providing a rigid substrate; forming the
flexible substrate on the rigid substrate; forming a gate electrode
of the thin film transistor on the flexible substrate; forming a
gate insulating layer covering the gate electrode; forming an
active layer of the thin film transistor on the gate insulating
layer; forming a source electrode and a drain electrode of the thin
film transistor, wherein the source electrode and the drain
electrode are connected to the active layer; forming a passivation
layer covering the active layer, the source electrode, and the
drain electrode of the thin film transistor; forming a
planarization layer on the passivation layer; forming the second
electrode on the planarization layer, wherein the second electrode
is connected to the drain electrode through a via hole penetrating
through the passivation layer and the planarization layer; forming
the photosensitive layer on the second electrode; forming the first
electrode on the photosensitive layer.
Optionally, the method further includes stripping the flexible
substrate off the rigid substrate to form a flexible photosensitive
sensor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a photosensitive sensor of some
embodiments of the present disclosure;
FIG. 2 to FIG. 9 are schematic flowcharts of manufacturing a
photosensitive sensor according to some embodiments of the present
disclosure; and
FIG. 10 is a flowchart of a method of manufacturing a
photosensitive sensor according to some embodiments of the present
disclosure.
DETAILED DESCRIPTION
In order to make technical problems, technical solutions, and
advantages of the embodiments of the present disclosure more
apparent, the present disclosure will be described in detail in
conjunction with accompanying drawings and specific
embodiments.
In a related photosensitive sensor, a thin film transistor is
combined with a photosensitive element. When the photosensitive
element is illuminated by light, charges in the photosensitive
element is transmitted to a reading line connected to the thin film
transistor via the thin film transistor, and an electrical signal
is transmitted to a processing circuit by the reading line so as to
realize detection of an optical signal. In order to avoid an
influence on performance of the thin film transistor by external
light, an active layer of the thin film transistor needs to be
shielded.
Embodiments of the present disclosure provide a photosensitive
sensor, a method of manufacturing the photosensitive sensor, and an
electronic device. The photosensitive sensor, the method of
manufacturing the photosensitive sensor, and the electronic device
may not only shield the active layer of the thin film transistor to
ensure the performance of the photosensitive sensor, but also
simplify a structure and a manufacturing process of the
photosensitive sensor to improve productivity of the photosensitive
sensor.
The embodiments of the present disclosure provide a photosensitive
sensor. The photosensitive sensor includes: a thin film transistor
and a photosensitive element on a substrate, wherein the
photosensitive element includes a first electrode, a second
electrode, and a photosensitive layer between the first electrode
and the second electrode; the second electrode is connected to a
drain electrode of the thin film transistor; an orthographic
projection of an active layer of the thin film transistor on the
substrate is within an orthographic projection of the second
electrode on the substrate; the second electrode includes at least
two conductive layers stacked one above another, at least one of
the at least two conductive layers is a light shielding metal
layer.
In some embodiments of the present disclosure, the second electrode
includes the light shielding metal layer, and the second electrode
may shield the active layer of the thin film transistor to prevent
external light from being irradiated onto the active layer of the
thin film transistor and thus affect performance of the thin film
transistor. Therefore, the structure and the manufacturing process
of the photosensitive sensor may be simplified, and the
productivity of the photosensitive sensor may be improved.
In specific embodiments, the photosensitive layer may be an organic
photosensitive material, and the organic photosensitive material
will generate electric charges after being irradiated by infrared
light or X-rays, and thus may be applied to scenes of fingerprint
recognition, facial recognition or X-ray recognition.
In a case that the photosensitive layer is made of the organic
photosensitive material, a conductive layer of the at least two
conductive layer is in contact with the photosensitive layer and is
made of ITO (indium tin oxide), in order to match a work function
of the organic photosensitive material and effectively lead out the
electric charges generated by the organic photosensitive material.
The ITO is matched with the work function of the organic
photosensitive material, and may effectively lead out the electric
charges generated by the organic photosensitive material.
In the at least two conductive layers stacked one above another,
the light shielding metal layer may be a metal layer made of Cu,
Ag, Al, Mo, or Ti, as long as the metal layer may block the light.
Optionally, the light shielding metal layer is made of Ag, because
the Ag and the ITO may be etched by using the same etching liquid,
so that when a pattern of the second electrode is formed by using a
wet etching process, the etching liquid is not required to be
replaced, and only the same etching liquid may etch both the Ag and
the ITO.
The second electrode may include two, three or more conductive
layers. In a specific example, the second electrode includes three
conductive layers, and the three conductive layers are made of ITO,
Ag, and ITO, respectively.
In order to irradiate external light onto the photosensitive layer,
the first electrode needs to be designed to be transparent, and the
first electrode may be a patterned metal pattern or an entire layer
of transparent conductive layer. Optionally, the first electrode is
formed as an entire layer of transparent conductive layer, such
that the first electrode may be arranged to an entirety of a
surface of the photosensitive sensor, so that a uniform electric
field is generated between the entirely planar second electrode and
the first electrode and is favorable to photo-generated
charges.
Further, the substrate may be a flexible substrate such that the
photosensitive sensor is a flexible photosensitive sensor that may
be applied to a wearable device.
In a specific example, as shown in FIG. 1, the photosensitive
sensor in the embodiments of the present disclosure includes: a
flexible substrate 2; a gate electrode 3 of a thin film transistor
on the flexible substrate 2; a gate insulating layer 4 on the gate
electrode 3; an active layer 5, a source electrode 6 and a drain
electrode 7 of the thin film transistor on the gate insulating
layer 4; a passivation layer 8 on the active layer 5, the source
electrode 6 and the drain electrode 7 of the thin film transistor;
a planarization layer 9 on the passivation layer 8; a second
electrode 11 on the planarization layer 9; a photosensitive layer
12 on the second electrode 11; a first electrode 13 on the
photosensitive layer 12. The second electrode 11 is connected to
the drain electrode 7 through a via hole VIA, and the second
electrode 11 is formed of a triple-layer structure including
ITO/Ag/ITO. The triple-layer structure may shield the active layer
of the thin film transistor to ensure the performance of the
photosensitive sensor, and may avoid a special step of
manufacturing an additional light shielding layer, thus simplifying
the structure and the manufacturing process of the photosensitive
sensor and improving a production capacity of the photosensitive
sensor.
Embodiments of the present disclosure also provide an electronic
device including the photosensitive sensor as described above.
The electronic device may be a display device including a product
or a component capable of displaying, such as a TV, a display, a
digital photo frame, a mobile phone, a tablet computer, and the
like, wherein the display device further includes a flexible
circuit board, a printed circuit board, and a backboard.
The electronic device may also be a fingerprint identification
device or a wearable device.
The embodiments of the present disclosure also provide a method of
manufacturing a photosensitive sensor. The method of manufacturing
the photosensitive sensor may be used to manufacture the
photosensitive sensor as described above. The method includes
forming a thin film transistor and a photosensitive element on a
substrate.
Forming the photosensitive element includes forming a first
electrode, a second electrode, and a photosensitive layer between
the first electrode and the second electrode, wherein the second
electrode is connected to the drain electrode of the thin film
transistor.
Forming the second electrode includes: forming the second electrode
by using at least two conductive layers stacked one above another,
wherein an orthographic projection of an active layer of the thin
film transistor on the substrate is within an orthographic
projection of the second electrode on the substrate, and at least
one of the at least two conductive layers is formed as a light
shielding metal layer.
In some embodiments of the present disclosure, the second electrode
includes a light shielding metal layer, so that no additional light
shielding layer is needed, and a channel of the thin film
transistor may be shielded by the second electrode, so as to
prevent external light from being irradiated to the active layer of
the thin film transistor and therefore affecting the performance of
the thin film transistor. Thus, a structure and a manufacturing
process of the photosensitive sensor may be simplified and the
production capacity of the photosensitive sensor may be
improved.
In a specific example, the photosensitive layer may be formed of an
organic photosensitive material, and the organic photosensitive
material will generate electric charges after being irradiated by
infrared light or X-rays, and thus may be applied to scenes of
fingerprint recognition, facial recognition or X-ray
recognition.
In a case that the photosensitive layer is made of the organic
photosensitive material, a conductive layer of the at least two
conductive layer in contact with the photosensitive layer is made
of ITO (indium tin oxide), in order to match a work function of the
organic photosensitive material and effectively lead out the
electric charges generated by the organic photosensitive material.
The ITO is matched with the work function of the organic
photosensitive material, and may effectively lead out the electric
charges generated by the organic photosensitive material.
In the at least two conductive layers stacked one above another,
the light shielding metal layer may be a metal layer made of Cu,
Ag, Al, Mo, or Ti, as long as the metal layer may block the light.
Optionally, the light shielding metal layer is made of Ag, because
the Ag and the ITO may be etched by using the same etching liquid,
so that when a pattern of the second electrode is formed by using a
wet etching process, the etching liquid is not required to be
replaced, and only the same etching liquid may etch both the Ag and
the ITO.
The second electrode may include two, three or more conductive
layers. In a specific example, forming the second electrode
includes forming the second electrode including three conductive
layers, wherein the three conductive layers are made of ITO, Ag,
and ITO, respectively.
In order to irradiate external light onto the photosensitive layer,
the first electrode needs to be designed to be light transmissible,
and the first electrode may be a patterned metal pattern or an
entire layer of transparent conductive layer. Optionally, the first
electrode is formed as an entire layer of transparent conductive
layer, such that the first electrode may be arranged to an entirety
of a surface of the photosensitive sensor, so that a uniform
electric field is generated between the entirely planar second
electrode and the first electrode and is favorable to
photo-generated charges.
Further, referring to FIG. 10, the method specifically includes the
following steps S1-S11.
S1: providing a rigid substrate;
S2: forming a flexible substrate on the rigid substrate;
S3: forming a gate electrode of the thin film transistor on the
flexible substrate;
S4: forming a gate insulating layer covering the gate
electrode;
S5: forming an active layer of the thin film transistor on the gate
insulating layer;
S6: forming a source electrode and a drain electrode of the thin
film transistor, wherein the source electrode and the drain
electrode are connected to the active layer;
S7: forming a passivation layer covering the active layer, the
source electrode, and the drain electrode of the thin film
transistor;
S8: forming a planarization layer on the passivation layer;
S9: forming the second electrode on the planarization layer,
wherein the second electrode is connected to the drain electrode
through a via hole penetrating the passivation layer and the
planarization layer, the second electrode includes three conductive
layers, the three conductive layers are sequentially made of ITO,
Ag and ITO;
S10: forming a photosensitive layer on the second electrode;
S11: forming a first electrode on the photosensitive layer.
After step S11, the flexible substrate may also be peeled off from
the rigid substrate, so that a flexible photosensitive sensor may
be obtained, which may be applied to a wearable device.
As shown in FIG. 2 to FIG. 9, the method of manufacturing the
photosensitive sensor of the present example specifically includes
following steps.
Step 1: as shown in FIG. 2, providing a rigid substrate 1, and
forming a flexible substrate 2 on the rigid substrate 1.
The rigid substrate 1 may be a glass substrate or a quartz
substrate. The flexible substrate 2 may be made of PI (polyimide).
Further, a buffer layer may be formed on the flexible substrate 2.
The buffer layer may be a single layer structure or a multilayer
structure, and the buffer layer may be formed of SiOx, SiNx, SiON
or the like.
Step 2: as shown in FIG. 3, forming a gate electrode 3 of the thin
film transistor on the flexible substrate 2.
Specifically, a gate metal layer having a thickness of about 500
.ANG. to 4000 .ANG. may be deposited by sputtering or thermal
evaporation on the flexible substrate after the step 1 is
completed; the gate metal layer may be made of Cu, Al, Ag, Mo, Cr,
Nd, Ni, Mn, Ti, Ta, W, and alloys of these metals; the gate metal
layer may be a single layer structure or a multilayer structure
formed of such as Cu\Mo, Ti\Cu\Ti, Mo\Al\Mo or the like. A
photoresist is coated on the gate metal layer, and the photoresist
is exposed by using a mask to form a photoresist-unreserved region
and a photoresist-reserved region, wherein the photoresist-reserved
region corresponds to a region at which a pattern of the gate
electrode 3 is located, the photoresist-unreserved region
corresponds to a region other than the region at which the pattern
of the gate electrode 3 is formed; a developing process is
performed, after which photoresist in the photoresist-unreserved
region is completely removed, and a thickness of photoresist in the
photoresist-reserved region remains unchanged; the gate metal layer
at the photoresist-unreserved region is completely etched away by
an etching process, and photoresist remained after the etching is
stripped off to form a pattern of the gate electrode 3.
Step 3: as shown in FIG. 4, forming a gate insulating layer 4 and
an active layer 5 of the thin film transistor.
Specifically, an insulating layer and a semiconductor layer may be
sequentially deposited on the flexible substrate 2 after the step 2
is performed; photoresist is coated on the semiconductor layer, and
the photoresist is exposed by using a halftone mask or a gray tone
mask. After the photoresist is developed, a photoresist
completely-reserved region, a photoresist partially-reserved
region, and a photoresist completely-removed region are formed; the
semiconductor layer corresponding to the photoresist
completely-removed region is removed by a wet etching process to
form a pattern of the active layer 5; the photoresist in the
photoresist partially-reserved region is subjected to an ashing
process, and the insulating layer corresponding to the photoresist
partially-reserved region is removed by using a dry etching process
to form a pattern of the gate insulating layer 4, and remaining
photoresist is stripping off.
The active layer 5 may be formed of a-Si, IGZO, IZO, IGZXO, IGZYO
or the like. The gate insulating layer 4 may be formed of an oxide,
a nitride or an oxynitride compound, and a corresponding reaction
gas is SiH.sub.4, NH.sub.3, N.sub.2 or SiH.sub.2Cl.sub.2, NH.sub.3,
N.sub.2.
Step 4: as shown in FIG. 5, forming the source electrode 6 and the
drain electrode 7 of the thin film transistor.
Specifically, a source/drain metal layer having a thickness of
about 2000 .ANG. to 4000 .ANG. may be deposited on the flexible
substrate by magnetron sputtering, thermal evaporation or other
film formation process after the step 3 is completed. The
source/drain metal layer may be made of Cu, Al, Ag, Mo, Cr, Nd, Ni,
Mn, Ti, Ta, W or the like and alloys of these metals. The
source/drain metal layer may be a single-layer structure or a
multilayer structure formed of such as Cu\Mo, Ti\Cu\Ti, Mo\Al\Mo or
the like. Photoresist is coated on the source/drain metal layer,
and the photoresist is exposed by using a mask to form a
photoresist unreserved region and a photoresist reserved region,
wherein the photoresist reserved region corresponds to regions at
which patterns of the source electrode 6 and the drain electrode 7
are located, the photoresist unreserved region corresponds to a
region other than the regions at which patterns of the source
electrode 6 and the drain electrode 7 are located; a development
process is performed, the photoresist in the photoresist unreserved
region is completely removed, and a thickness of the photoresist in
the photo reserved region remains unchanged; the source/drain metal
layer in the photoresist unreserved region is completely etched
away by an etching process, and the remaining photoresist is
stripped off to form the source electrode 6 and the drain electrode
7.
Step 5: as shown in FIG. 6, forming a passivation layer 8 and a
planarization layer 9.
Specifically, a layer of passivation material and a layer of
planarization material are sequentially deposited on the flexible
substrate after the step 4 is performed. The planarization material
may be an organic photosensitive resin, and after an exposure is
performed, the planarization layer 9 with a via hole VIA formed
therein is formed. By using the pattern of the planarization layer
9 as a mask, the layer of passivation material is dry-etched to
form the passivation layer 8 with the via hole VIA formed
therein.
Step 6: as shown in FIG. 7, forming a second electrode 11.
Specifically, ITO, Ag, and ITO may be sequentially deposited on the
flexible substrate after the step 5 is performed, and the
triple-layer structure including the ITO/Ag/ITO is patterned to
form a pattern of the second electrode 11, and the second electrode
11 is connected to the drain electrode 7 through the via hole VIA
in the passivation layer 8 and the planarization layer 9.
Step 7: as shown in FIG. 8, forming a photosensitive layer 12 and a
first electrode 13.
Specifically, a layer of photosensitive material may be deposited
on the flexible substrate after the step 6 is performed, and the
layer of photosensitive material may be patterned to form the
photosensitive layer 12.
A transparent conductive material is then deposited, and the
transparent conductive material is patterned to form the first
electrode 13.
Step 8: as shown in FIG. 9, stripping off the flexible substrate 2
from the rigid substrate 1 to obtain a flexible photosensitive
sensor.
Specifically, the flexible substrate 2 may be stripped off from the
rigid substrate 1 by using LLO (a Laser Lift Off technique).
The embodiments of the present disclosure have following beneficial
effects. In the above solutions, the second electrode includes the
light shielding metal layer, so that no additional light shielding
layer is needed, and a channel of the thin film transistor may be
blocked by the second electrode to prevent external light from
being irradiated onto the active layer of the thin film transistor
and affecting the performance of the thin film transistor. A
structure and a manufacturing process of the photosensitive sensor
may be simplified and a production capacity of the photosensitive
sensor may be increased.
In the method embodiments of the present disclosure, sequence
numbers of the steps are not used to limit a sequence of steps. For
those skilled in the art, variations of the sequence of the steps
without any creative work by one of ordinary skills in the art are
also within the scope of the present disclosure.
Unless otherwise defined, technical terms or scientific terms used
in the present disclosure are intended to have ordinary meanings
understood by one of ordinary skills in the art to which the
present disclosure belongs. Such words as "first", "second", or the
like used in the present disclosure do not denote any order,
quantity, or importance, but are used to distinguish different
components. Such word "including" or "comprises" or the like means
that an element or an item preceding the word encompasses an
element or article or equivalent element or article thereof listed
behind the word, without precluding other elements or articles.
Such words as "connected" or "connecting" or the like are not
limited to physical or mechanical connections, but may include
electrical connections, whether direct connections or indirect
connections. Words such as "upper", "lower", "left", "right", etc.
are only used to indicate a relative positional relation, and when
an absolute position of an object being described is changed, the
relative positional relation may also be changed accordingly.
It will be understood that when an element such as a layer, a film,
a region or a substrate is referred to as being "on" or "below"
another element, the element may be "directly on" or "directly
below" the another element, or there may exist an intermediate
element.
The above are optional embodiments of the present disclosure, and
it should be noted that those skilled in the art may also make
several improvements and refinements without departing from the
principles of the present disclosure. The improvements and
refinements should also be considered to be within the protection
scope of the present disclosure.
* * * * *